Foldable extension ladder

ABSTRACT

This invention relates to a foldable extension ladder of channel shaped or tubular metal comprising a plurality of side rail sections hinged together at their end portions so that when the ladder is assembled into operating position, the end of one side rail section will project into a sleeve portion of the hinge connected to an adjoining side rail section so as to be reinforced and guided thereby. The rungs have end portions pivoted to struck out portions of the side rail sections, which end portions project into the hollow side rail sections so as to be directly supported by the main panels of such side rail sections.

United States Patent 1191 Deese May 1,1973 7 FOLDABLE EXTENSION LADDER Primary Examiner-Reinaldo P. Machado [76] I v Att0rneyWilliam J. Ruano Samuel H. Deese, 1005 Brown St., Bel Vernon, Pa. 15012 June 10, 1971 [22] Filed:

211 App]. No.: 151,684

tions so that when the ladder is assembled into operating position, the end of one side rail section will pro- 33 m mm 4 NW6 1 E3 6 I l "2 8 l. r. m 1 m d .d .3 l: 2 00 555 [.11.

ject into a sleeve portion of the hinge connected to an adjoining side rail section so as to be reinforced and guided thereby. The rungs have end portions pivoted References Cited UNITED sTArEs PATENTS to struck out portions of the side rail sections, which end portions project into the hollow side rail sections so as to be directly supported by the main panels of 3,081,840 Hire uch side raj] sections 3,474,881 Green................... ...l82/l63 3 Claims, 8 Drawing Figures Patented May I, 1973 INVENTOR SAMUELtLDEESE BY xix his ATTORNEY This invention relates to a foldable extension ladder comprised of sections hinged together so as to be folded or collapsed like an accordion into a compact structure.

Foldable extension ladders are known in the art but have not been adopted'commercially to any appreciable extent for the reason that they are heavy and cumbersome in construction, generally requiring solid elements, and, particularly, because the hinged parts tend to get out of alignment and make the ladder unsafe for further use.

'An object of the present invention is to provide a novel foldable extension ladder which is devoid of the abovenamed disadvantages and which is very light in weight and of tubular or channel construction and wherein hinged joints are interlocked and made very secure and safe whereby the ladder will have relatively long life and may be used with a high degree of reliance.

A more specific object of the invention is to provide a foldable extension ladder wherein the ends of channel shaped rungs are pivotal into the interior of tubular side rails so that the weight of the person climbing the ladder will be supported by the interior panels of the side rails, rather than by attached elements, such as brackets, and wherein hinged joints between sections of each side rail are interfitted and interlocked, one within the other, to provide structural reinforcement throughout the entire length of the hinged joints and of the ladder.

Other objects and advantages will become more apparent from a study of the following description, taken with the accompanying drawing, wherein:

FIG. 1 is a top, perspective view of a ladder embodying the principles of the present invention and shown in collapsed or folded position;

FIG. 2 is a'fragmentary, somewhat enlarged side view showing two pairs of adjoining sections and their hinged joints;

F IG 3 is an enlarged, fragmentary, elevational view of the hinge forming one of the hinged joints;

FIG. 4 is a side view of the hinged joint shown in FIG. 3;

FIG. 5 is a fragmentary, elevational view, partly in cross-section, of one of'th'erungs of the ladder and its pivotal connections to theside rails when in assembled position;

FIG. 6 is a top view of the construction shown in FIG. 5 and as viewed generally along line VI-Vl of FIG. 5;

FIG. 7 is a fragmentary view showing a locking bar for securing the collapsed sections firmly together in one unit for easy carrying; and

FIG. 8 is a fragmentary, elevational view of the ladder shown in assembled form ready for use.

Referring more particularly to FIG. I of thedrawing,

.numeral 1 generally denotes a foldable extension ladder of metal, such as steel or aluminum, in channelshaped or tubular form and shown in folded or collapsed condition. The particular example illustrated shows two channel shaped side rails 2, each comprised of four sections pivotally hinged together by hinged joints generally denoted by numeral 4.

FIG. 2 shows more clearly the construction of one of the hinges 4, comprising a clamp portion 5 rigidly secured to one of the side rails sections 2 by bolts 6 and extending well beyond the end 13 of such side rail section. Clamps is tapered at 7 and hingedly connected to clamp portion 8, secured by bolts 10 to the adjoining side rail section, by a pivot bolt 8. It should be particu- I larly noted that when the side rail sections, shown at the top right end of FIG. 2, are pivoted about pivot bolt 8 to form a continuous side rail member, as illustrated in FIG. 4, clamp 9 which terminates short of the end of its side rail section, will allow the projecting end portion of its side rail section to project well into the confines of clamp portion 5 up to the dotted line position indicated by numeral 13 where it butts against the end of the ajoining side rail portion. Thus clamp portion 5 will snugly surround an enclose the end portion of the adjoining side rail portion so as not to permit the adjoining said rail sections to get out of butting alignment.

Another important feature of the invention resides in the specific pivotal connection between each rung 3 and the side rails 2, as illustrated more clearly in FIGS. 5 and 6. FIG. ,5 shows stamped out portions 15 emerging from the inner flanges of side rails 2. Registering holes are formed in the stamped out portions 15 and pivot bolts 16 are extended therethrough in an offset relationship to the width of the cut-out portions, that is,closer to one end than the other, as illustrated more clearly in FIG. 6. As shown in full lines in FIG. 6 side rails 2, which are channelshaped, thus may be pivoted about pivot bolts 16 as a center through to the position shown in dotted line whereby the main flange of rung 3 bears directly against the outer surface of the side rails 2 to provide a firm support therefor when the ladder is in collapsed position. However, it should be particularly noted that when the rung is in operative position, as shown in FIG. 5, its end portions protrude into the interior of the channeled side rail sections 2 so that the entire weight of the person climbing the ladder will be borne directly by the main flange or panel of the side rail sections as distinguished from being borne by an attachment, such as an angle section (not shown) attached to such main flange. Also the side edges of the cut-out portions serve as stops for the sides of the rungs.

In operation, when the ladder is: in collapsed position as shown in FIG. 1, its sections are hinged about bolts 8 so as to extend longitudinally in end-to-end relationship while the side railsare in the position shown in dotted lines in FIG. 6. Then by grasping a side rail section on each side and turning it about its pivotal bolt 16 to the full line position, that is, at right angles to the rungs, all the side rail sections will turn together and be locked so that they can no longer pivot about their hinge bolts 8.

FIG. 7 shows locking bar 18 which is pivotally connected at ends 19 and 20 to the side rails for locking them together in collapsed condition to enable easy carrying of the folded ladder assembly. One of the ends, .such as 19, may have a hook to encircle a bolt shank connected to the side rail section.

Although side rails 2 are shown channel-shaped, they may, like rungs 3, be of rectangular tubular form.

Thus it will be seen that I have provided an efficient,

light weight, metallic ladder of channeled or tubular cross-section, having interfitting and interlocking side rail sections to assure continuous alignment thereof and having pivotal connections between the ends of the rungs and side rail sections of such construction that the entire weight. of the person climbing the ladder will be borne directly by the main panel or flange of the side rails..

While I have illustrated and described a single specific embodiment of my invention, it will be understood that this is by way of illustration only and that various changes and modifications may be made within the scope of the following claims.

I claim:

1. A foldable extension ladder comprising a pair of hollow side rails, each of said side rails comprising a plurality of sections, hinges interconnecting said sections in a manner to allow the sections to be folded like an accordion, a plurality of evenly spaced, vertically disposed pairs of struck-out portions emerging from the inner panels of saidside rail sections and being provided with registering holes, a plurality of hollow tubular rungs, pivot bolts extending through said holes for pivotally connecting said rungs to said side rail sections whereby the ends of said rungs will project into the ho]- low interior of said side rails so that weight applied to said rungs will be directly supported by the inner panels of said side rails, said pivot bolts being arranged to allow said side rail sections to turn from operative position so that they will abut against one of the side walls of said rungs when collapsed.

2. A foldable extension ladder as recited in claim 1, wherein each hinge has a portion bolted to an end portion of adjoining side rail sections and has a hinge bolt pivotally connecting said hinge portions in a manner so that the end of one side rail section projects into and is snugly enclosed by a hinge portion secured to the adjoining side rail section so as to insure that the complementary ends of said side rail sections are retained in abutting relationship and are reinforced by said hinge portions.

3. A foldable extension ladder as recited in claim 1 together with a locking bar for holding together said side rail sections when in collapsed condition. 

1. A foldable extension ladder comprising a pair of hollow side rails, each of said side rails comprising a plurality of sections, hinges interconnecting said sections in a manner to allow the sections to be folded like an accordion, a plurality of evenly spaced, vertically disposed pairs of struck-out portions emerging from the inner panels of said side rail sections and being provided with registering holes, a plurality of hollow tubular rungs, pivot bolts extending through said holes for pivotally connecting said rungs to said side rail sections whereby the ends of said rungs will project into the hollow interior of said side rails so that weight applied to said rungs will be directly supported by the inner panels of said side rails, said pivot bolts being arranged to allow said side rail sections to turn 90* from operative position so that they will abut against one of the side walls of said rungs when collapsed.
 2. A foldable extension ladder as recited in claim 1, wherein each hinge has a portion bolted to an end portion of adjoining side rail sections and has a hinge bolt pivotally connecting said hinge portions in a manner so that the end of one side rail section projects into and is snugly enclosed by a hinge portion secured to the adjoining side rail section so as to insure that the complementary ends of said side rail sections are retained in abutting relationship and are reinforced by said hinge portions.
 3. A foldable extension ladder as recited in claim 1 together with a locking bar for holding together said side rail sections when in collapsed condition. 